# Potential of Quantitative α‑Amylase or Trypsin Inhibition by Refined and Whole Wheat and Einkorn Using High-Performance Thin-Layer Chromatography–NanoGIT versus Conventional Spectrophotometry

## TL;DR

This study compares the inhibition of enzymes by different wheat types using a new method that combines chromatography and nanoGIT assays.

## Contribution

The novel HPTLC–nanoGIT workflows provide detailed insights into enzyme inhibition and metabolite profiles.

## Key findings

- Einkorn showed lower α-amylase inhibition compared to refined and whole wheat.
- High extract concentrations of all cereals showed 100% trypsin inhibition.
- The new method revealed specific interactions and metabolite profiles not detectable by conventional methods.

## Abstract

The current analysis
of α-amylase/trypsin inhibitors (ATIs)
is complicated due to the missing link between inhibition potential
and inhibitors. Two on-surface assays (nanoGIT) were developed to
quantify the inhibition of α-amylase and trypsin by flour extracts
of refined wheat, whole wheat, and einkorn, followed by direct analysis
(on the same surface) of the metabolisation products via high-performance
thin-layer chromatography (HPTLC). The HPTLC–nanoGIT (amylolysis
inhibition)–FLD/Vis revealed a lower α-amylase inhibition
of einkorn than refined or whole wheat, whereby both latter wheat
types showed no differences. The HPTLC–nanoGIT (proteolysis
inhibition)–Vis confirmed only partially the 100% inhibition
at high extract concentrations of the three cereal types obtained
by the spectrophotometric trypsin inhibition assay. The HPTLC–nanoGIT
workflows not only confirmed the inhibitory effects obtained by spectrophotometric
assays but also provided substantial resolution of saccharide-specific
interactions and specific profile patterns of the released individual
metabolisation products.